refactor: 💡 React components to consume appConfig using Context (#852)

* refactor: 💡 React components to consume appConfig using Context

React components to consume app configuration using React Context and
React Hooks. Non React components to continue using global variable
window.config. Related documentation also changed.

Closes: #725

* refactor: 💡 Removing unecessary code

On current React component there is no need to import useContext method
from React, so, removing it.

* refactor: 💡 Code review

Code review. Minor changes based on review inputs and moving userManager
to an init method

BREAKING CHANGE: #725

Closes: #725

* docs: don't include implementation detail in docs

* docs: don't include implementation detail in docs

* docs: no need to specify implementation details in employment recipe

* docs: no need to specify implementation details in deployment recipe

docs/latest/deployment/recipes/nginx--image-archive.md

@@ -121,11 +121,7 @@ likely want to update:
 
 #### OHIF Viewer
 
-The OHIF Viewer's configuration is imported from a static `.js` file and made
-available globally at `window.config`. The configuration we use is set to a
-specific file when we build the viewer, and determined by the env variable:
-`APP_CONFIG`. You can see where we set its value in the `dockerfile` for this
-solution:
+The OHIF Viewer's configuration is imported from a static `.js` file. The configuration we use is set to a specific file when we build the viewer, and determined by the env variable: `APP_CONFIG`. You can see where we set its value in the `dockerfile` for this solution:
 
 `ENV APP_CONFIG=config/docker_openresty-orthanc.js`
 

docs/latest/deployment/recipes/user-account-control.md

@@ -122,11 +122,7 @@ likely want to update:
 
 #### OHIF Viewer
 
-The OHIF Viewer's configuration is imported from a static `.js` file and made
-available globally at `window.config`. The configuration we use is set to a
-specific file when we build the viewer, and determined by the env variable:
-`APP_CONFIG`. You can see where we set its value in the `dockerfile` for this
-solution:
+The OHIF Viewer's configuration is imported from a static `.js` file. The configuration we use is set to a specific file when we build the viewer, and determined by the env variable: `APP_CONFIG`. You can see where we set its value in the `dockerfile` for this solution:
 
 `ENV APP_CONFIG=config/docker_openresty-orthanc-keycloak.js`